The present invention relates to a method for manufacturing socks with a circular knitting machine having at least two feeds or drops.
As is known, in the conventional production of socks with circular machines the heel and toe of the sock are formed by using a single feed or drop of the machine and by actuating the needle cylinder with an alternating rotary motion about its own axis through a rotation angle of approximately 180°, so as to make one half of the needle cylinder pass at said feed or drop. The needles of this half of the needle cylinder are made to knit at the feed or drop being considered, and their number is gradually decreased, increasing the number of needles excluded from knitting starting from the lateral ends of the set, in a first step, and gradually increased in a second step, so as to achieve the characteristic pouch-like shape for the heel and the toe.
Formation of the heel and toe of the sock, due to the need to actuate the needle cylinder with an alternating rotary motion about its own axis and at a reduced speed owing to the fact that the direction of rotation of the needle cylinder must be reversed cyclically, considerably affects the overall duration of the sock production cycle. In order to reduce the time required to form the heel and the toe of socks, methods have been proposed which allow to form a pouch at the heel and toe by actuating the cylinder with a continuous rotary motion about its own axis and by interrupting, by cutting the thread, the additional rows of stitches that provide the pouch. Although these methods unquestionably speed up the sock production cycle, they have the drawback of producing a sock that is not fully satisfactory both from an aesthetic standpoint and as regards comfort, due to the presence of the cut trailing threads on the reverse side of the sock.
Methods for producing the heel and toe have also been devised which again provide for the actuation of the needle cylinder with an alternating rotary motion about its own axis but use multiple feeds or drops of the machine, so as to produce, at each rotation in one direction or in the opposite direction of the needle cylinder, a plurality of rows of stitches so as to speed up the production of the heel or toe. These methods have the drawback that they do not provide a result that is aesthetically comparable with what can be obtained with the conventional method, and the advantage in terms of speed is only partial, since in order to involve a plurality of feeds it is necessary to increase the extent of the alternating rotation of the needle cylinder about its own axis.